On a scale of 1 to 10 - How difficult to code a Bit torrent Client

I was looking for an interesting project to work on - something challenging, but not impossible. I have seen the detailed bit - torrent protocol is available online - and so are lots and lots of open source torrent clients.

I was looking at the code for a command line torrent client that is written in C++ called originally 'Ctorrent'. It is now called Enhanced Ctorrent. It would be interesting to learn all the ins and outs of p2p stuff.

But on a scale of 1 to 10 how difficult would such a project be (Bearing in mind I will have lots of open source code to reference)? I am only aiming to do a working console program - nothing fancy!

I reckon its around 7/10 and possibly would take 3-6 months of regular work to finish this project.